Semiconductor packages widely used in electronics (e.g., personal computers), communication devices, etc. have been more highly functionalized or miniaturized in recent years. Along with this, the high integration or high-density packaging of each component for semiconductor packages has been increasingly accelerated. In, for example, printed wiring boards (PWBs) or printed circuit boards (PCBs) packed with electronic components, colored substrates are used from the viewpoint of the visual recognition of wiring, the aesthetic installation in products, etc., and prepregs or the like impregnated with a colored curable resin composition containing a colorant are routinely used as materials.
As for techniques related to the colored curable resin composition, for example, Patent Literature 1 discloses a colored curable resin composition containing (a) a color material, (b) a solvent, (c) at least one member selected from the group consisting of a polymerizable monomer and a binder resin, (d) a photopolymerization initiator, and (e) a polymer surfactant having a fluoro aliphatic group in a side chain. Patent Literature 2 discloses a method for producing a resin composition, including the steps of: (1) dissolving and/or dispersing (B) a colorant in (A) a dispersion of an inorganic filler dispersed in a solvent; and (2) then dissolving (C) a novolac-based epoxy resin therein. Patent Literature 3 discloses a technique of adding a synthetic resin colorant or the like containing an infrared absorber such as a naphthoquinone derivative, a pigment such as an azo-anthraquinone derivative, etc. to an epoxy resin.
Meanwhile, resin compositions supplemented with an alkenyl-substituted nadimide are used as curable resin compositions for use in prepregs or the like. The alkenyl-substituted nadimide is expected to have advantages such as solubility in many solvents routinely used, excellent compatibility with epoxy resins or the like, and obtainment of cured products (prepregs, etc.) excellent in physical properties such as high heat resistance.